1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, 13 * software distributed under the License is distributed on an 14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 15 * KIND, either express or implied. See the License for the 16 * specific language governing permissions and limitations 17 * under the License. 18 */ 19 20 package org.apache.myfaces.orchestra.viewController; 21 22 /** 23 * An interface for use with the InterfaceViewControllerExecutor. 24 * <p> 25 * When the InterfaceViewControllerExecutor has been selected as the technique for mapping 26 * lifecycle events onto bean methods, then the target bean must implement this interface 27 * in order to get callbacks. 28 * <p> 29 * Note that the expression "view controller bean" is used to generally refer to an object 30 * that can handle lifecycle events for a view. Such beans may implement this interface, but 31 * may not - they might be accessed via the ReflectiveViewControllerExecutor or other 32 * implementations that do not require this interface. 33 */ 34 public interface ViewController 35 { 36 /** 37 * This method will <i>always</i> be called before any other method is invoked 38 * on any backing bean for the current request. It is invoked once for each 39 * request. 40 * <p> 41 * This callback could possibly be better named "notifyBeginRequestUsingThisView" 42 * or similar, as it is invoked per request. 43 * <p> 44 * There are three different situations in which initView callbacks occur: 45 * <ol> 46 * <li> 47 * A view is just being rendered.<br> 48 * The initView callback gets called once (at BeforeRender) 49 * </li> 50 * <li> 51 * A postback is processed, no navigation occurs.<br> 52 * The initView callback gets called once (at AfterRestoreView) 53 * </li> 54 * <li> 55 * A postback occurs, navigation to a different view instance occurs.<br> 56 * The initView callback gets called once for the original view, and then once for the new view. 57 * </li> 58 * </ol> 59 * <p> 60 * Note that the condition tested is whether the <i>view instance</i> has changed; if navigation causes 61 * a new view root to be created then the initView callback occurs even if that view root has the 62 * same viewId [1]. 63 * <p> 64 * Note [1]: Orchestra versions 1.3 and earlier test only the viewId string. 65 */ 66 public void initView(); 67 68 /** 69 * This method will be invoked before any "action" callbacks related to buttons, 70 * links, etc. are invoked on backing beans for the current request. 71 * <p> 72 * For JSF, there is an exception: for command components marked as "immediate", 73 * the associated action method is invoked before this callback occurs. If that 74 * method then performs navigation then this callback will not occur at all. 75 * <p> 76 * Note also that for JSF, if validation failures occur then this callback will 77 * not be invoked (as actions are skipped). 78 */ 79 public void preProcess(); 80 81 /** 82 * This method will be invoked just before starting to render output to the user. 83 */ 84 public void preRenderView(); 85 }